Summary

A vulnerability in Microsoft Internet Explorer could allow an unauthenticated, remote attacker to execute arbitrary code.

The vulnerability is due to improper memory operations performed by the affected software when handling crafted content. An unauthenticated, remote attacker could exploit this vulnerability by persuading a user to view a malicious website. A successful exploit could allow the attacker to execute arbitrary code with the privileges of the user. If the user holds elevated privileges, the attacker could completely compromise the targeted system.

Microsoft has confirmed the vulnerability in a security bulletin and released software updates.

Indicators of Compromise

Microsoft Internet Explorer versions 9 and 10 are affected when running on the following Microsoft products:

Windows Vista and x64 Edition SP2

Windows Server 2008 for 32-bit and x64-based Systems SP2

Windows 7 for 32-bit and x64-based Systems SP1

Windows Server 2008 R2 for x64-based Systems SP1

Windows 8 for 32-bit and 64-bit Systems

Windows Server 2012

Windows RT

Technical Information

The vulnerability is due to a memory corruption error that may occur when the affected software attempts to access an object in memory.

An unauthenticated, remote attacker could exploit this vulnerability by providing a malicious link and persuading the user to view a malicious website or follow the malicious link. If the attack is successful, a memory corruption error could allow the attacker to execute arbitrary code with the privileges of the user. If the user holds elevated privileges, the attacker could completely compromise the system.

Analysis

To exploit the vulnerability, the attacker may provide a link that directs a user to a malicious site and use misleading language or instructions to persuade the user to follow the provided link.

Microsoft has corrected the vulnerability by modifying the way the affected software performs memory operations when handling crafted content.

Safeguards

Administrators may consider configuring Internet Explorer to prompt users before running Active Scripting or ActiveX controls by setting the Internet and Local Intranet security zone settings to High. Alternately, administrators could disable Active Scripting and ActiveX controls in these security zones.

Users are advised not to open e-mail messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in e-mail messages are safe, they are advised not to open them.

Administrators may consider using the Microsoft Baseline Security Analyzer (MBSA) scan tool to identify common security misconfigurations and missing security updates on system endpoints.

Administrators are advised to monitor affected systems.

Vendor Announcements

Microsoft has released a security bulletin at the following link: MS13-047

Fixed Software

Microsoft customers can obtain updates directly by using the links in the security bulletin. These updates are also distributed by Windows automatic update features and available on the Microsoft Update service. Microsoft Windows Server Update Services (WSUS), Systems Management Server, and System Center Configuration Manager can assist administrators in deploying software updates.

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